In the current practice of gastrointestinal (GI) endoscopy, ambient room air is predominantly used as a gaseous media for distending some portion of the GI tract when performing this procedure. Within the practice of medicine, it is widely known that when distending the GI tract (or other body cavities, such as in the case of laparoscopy) with ambient room air, the constituent nitrogen gas found in ambient room air is not readily remediated through normal metabolic and respiratory process. Thus, post medical procedure, gas pockets of nitrogen are not easily tolerated by the human body and lead to post-procedure pain and discomfort until they resolve themselves. Similarly, oxygen found in ambient room air is also not as easily absorbed. Carbon dioxide (CO2), on the other hand, may be very quickly absorbed and expelled via normal respiration post-procedure by an individual undergoing a medical procedure wherein the distention of a body cavity by insufflation is required. As one skilled in the art will appreciate, it is common to use CO2 insufflation (via the use of an electro-pneumatic insufflator) for medical procedures involving abdominal or gynecological laparoscopy and more recently virtual colonoscopy. For these medical procedures, closed anatomical cavities are distended (much like a balloon) with an electro-pneumatic insufflator. The electro-pneumatic insufflators utilized in such procedures delivers CO2 through a trocar, entry needle, or catheter at a constant regulated flow rate until a selected pressure is reached to maintain the desired level of distention for the duration of the medical procedure. Should there be any leakage or absorption of CO2 during laparoscopic or virtual colonoscopy procedure, the electro-pneumatic insufflator makes up for the shortfall by delivering the additional CO2 to maintain the set distention pressure.
However, in medical procedures utilizing an endoscope for gastrointestinal endoscopy, distention media air passes through lumens of the endoscope to the patient's GI tract. Such distention of the GI tract using current equipment typically involves the physician performing the procedure wherein a port or valve on the control section of the endoscope is manually manipulated by the physician over the course of the procedure to achieve the desired level of distention. Unlike laparoscopic and virtual colonoscopy procedures, the distention media is not automatically delivered at a specified flow rate until the anatomic cavity reaches a specified pressure or level of distention where thereafter it is maintained in equilibrium at a set pressure. For GI endoscopy, GI tract insufflation is typically localized to support navigation of the endoscope and perform any evaluation or distal end articulated procedures through the scope. Additionally, supporting the use of the endoscope, irrigation and suction features are also frequently used. Thus, in current systems and methods for GI endoscopy, the distention gas (ambient room air) is supplied to the endoscope at a continuous flow rate with a maximum source pressure well in excess of the clinical requirements for laparoscopy and virtual colonoscopy. Through manipulation of the endoscope controls (including, in most cases a bypass vent valve), excess distention gas that is not directed through the endoscope to the patient is bypassed to atmosphere. Currently available endoscopy light sources have simple diaphragm compressor pumps integrated therein to supply room air as a distention media through the lumens of the endoscope. In this scenario, there is no accounting for any specific volume of air and the pump typically runs continuously for the duration of the procedure.
There are also rudimentary CO2 insufflation support devices that are currently marketed for endoscopy procedures. However, these are non-electronic devices that consist of a pressure regulator and flow restrictor in series with a bottled gas source (such as a CO2 tank) that mimic the equivalent flow and pressure output as that of the ambient room air compressor in the endoscope light source. Furthermore, such existing CO2 insufflation support devices have the disadvantage of continually discharging CO2 into the surrounding atmosphere whereby ventilation adequacy may be of concern. Furthermore existing CO2 insufflation support devices may also quickly deplete CO2 supplies by continuously venting unused CO2 to the procedure room and thus may require frequent changing of the CO2 supply cylinders in fluid communication therewith.
Thus, there exists a need for a system, method, and/or computer program product for precisely controlling the flow of insufflating gas (such as CO2) to a GI endoscope in response to detected pressure changes that may be associated with a physician's control inputs to a control portion of the GI endoscope. In addition, there exists a need for a system and method for automatically adjusting the flow rate between a “standby” CO2 conservation mode (characterized by a low flow rate) to a clinically-active insufflation mode (characterized by a higher flow rate) with no intervention on the part of the user except for the normal control inputs to the endoscope. There also exists a need for a computer program product for controlling an electro-pneumatic insufflator, such that a user may input insufflation gas control parameters in order to optimize the control of insufflating gas for a selected procedure.